Latest Discussions : Electrical & Lighting


05:50PM | 11/08/02
Member Since: 11/07/02
9 lifetime posts
Can i convert my 220 window unit circuit to a 110 window unit circuit just by changing my receptical and switching to a 20 amp breaker? It has no. 10 wire.


06:37PM | 11/08/02
Member Since: 08/19/02
29 lifetime posts
You can use a 20-amp single-pole breaker but you'll also need to use a 20-amp receptacle.

And you'll need to wrap the 10 AWG wire around the terminal screws on the receptacle (clockwise all the way around, but not extending beyond the screw). Be sure to tighten all screws securely.

On the receptacle, you'll need a hot coming from the breaker and going to the copper-colored terminal and a return coming from the neutral bar in the panel and going to the silver-colored terminal.

The bare copper grounding wire must come from the grounding bus bar at the panel to the green screw on the receptacle if the breaker is located in a sub-panel, or the neutral bar if it's in the main panel. Just determine where the other bare grounding wires are connected in the panel and do likewise.

You don't say what wires are coming into the receptacle box and there are several possibilities:

1. Red, black, white and bare ground, whereas the red and black were used for the 240 hots and the white was capped off and doing nothing.

If this is your wiring, you can use either the red or black for the hot and the white for the 120v return. Put a wire nut on the wire you don't use in both the receptacle box and the panel.

2. Black, white and bare ground, whereas the black and white were used as the hots and, hopefully, the white had a black tape or something on it designating it a hot wire.

If this is the wiring, it's all ready for 120v. The black will be the hot and the white will be the return.

The bare ground goes in the same places as mentioned before in either scenario.

If there's anything you don't understand about any of this, either post back with some questions or get a licensed electrician to help you.

EDIT: It wouldn't hurt to put a note explaining what you've done in the panel, so another person working with your wiring will know.

[This message has been edited by HBB (edited November 08, 2002).]


02:21AM | 11/10/02
Member Since: 11/05/01
98 lifetime posts
You only need a 20 amp receptacle if its a single receptacle. If its a standard duplex you can use a 15 amp receptacle. On whatever you use be sure to see if it allows connection from a #10 conductor. Some do not. You will then have to pigtail a # 12.


03:53AM | 11/11/02
Member Since: 08/19/02
29 lifetime posts
How can a 20-amp breaker protect a 15-amp receptacle?


04:50AM | 11/11/02
Member Since: 09/17/02
524 lifetime posts
It doesn't protect the recepticle it protects the wire.


06:30AM | 11/11/02
Member Since: 08/19/02
29 lifetime posts
A receptacle is simply a conductor, just like a wire, and becomes an extension of the wire on the way to the appliance.

A breaker is sized to protect the weakest link in a circuit. And a 20-amp breaker will not protect a 15-amp receptacle.

Why do you think they make 20-amp receptacles that will accept both 15- and 20-amp plugs? They're made to be used when the wire is 12 AWG or above and the breaker is 20-amp.

Why do you think manufacturers QUIT MAKING 15-amp receptacles whose back-stabs would accept 12 AWG wire? The back-stabs on 15-amp receptacles are sized now to DISALLOW the use of 12 AWG wire.

A 20-amp breaker will protect nothing rated at less than 20 amps anywhere in a circuit, whether it's a wire, receptacle, plug or whatever.

Otherwise, why are these things rated at all?

Or maybe that doesn't apply in Canada.

Your answer wouldn't be my choice, especially considering that a combination 15/20-amp duplex receptacle costs very little more than a plain 15-amp.


11:53AM | 11/11/02
Member Since: 07/28/02
4 lifetime posts

Single receptacles on an individual branch circuit.

A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit.

Receptacle ratings.

Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3).

Table 210.21(B)(3)
Receptacle ratings for various size circuits.

Circuit rating=========Receptacle rating
15====================Not over 15
20====================15 or 20
40====================40 or 50

Therefor by the NEC it is permissable to protect a circuit supplying two or more 15 amp receptacles with a 20 amp overcurrent device.

So in recap:
15a breaker 15a receptacles whether they be single or duplex.

20a breaker 15a receptacles only when there are two or more on the branch circuit. (This includes a duplex receptacle with two receptacles on a single yoke)

20a breaker may protect either a single 20a receptacle or two or more 20a receptacles.

[This message has been edited by DaveB.inVa (edited November 11, 2002).]


01:55PM | 11/11/02
Member Since: 08/19/02
29 lifetime posts

Thanks much for the NEC references. I've got a copy on the way, but it hasn't arrived yet.

Still wouldn't have changed my thinking.

I expected it to say something like that because I know it's common practice to use 15-amp receptacles on 20-amp breakers.

The NEC notwithstanding, I nevertheless stand by the logic of my points made above.

And I'll continue to pay a buck or so extra to put combination 15/20-amp receptacles on 20-amp circuits protected by 20-amp breakers. Common sense and a respect for device ratings tell me that's why such receptacles exist.

As for the back-stabs on currently manufactured 15-amp receptacles no longer being large enough to accept 12 AWG wire, it's my opinion that those things should be outlawed altogether anyway. They're the lazy man's way of hooking up a receptacle and they have a definite tendency to fail -- especially those on cheap receptacles.

Anyone who owns blue-collar rental properties, as I did once, can very likely relate story after story of the strange and idiotic appliances, many with strange and idiotic adaptations, that tenants will plug into a common wall outlet.

There are few things that can terrify a landlord like a receptacle so hot it's cherry-red.

But I welcome any further thoughts you may have on these issues.

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